1. Field of the Invention
Embodiments of the present invention generally relate to an apparatus and method for opening and closing flow passages through a tubular body, and more particularly, to a system for controlling the flow of fluids in wellbore operations.
2. Description of the Related Art
FIG. 1 shows a cross-sectional view of a typical hydrocarbon well 10. The well 10 includes a vertical wellbore 12 and thereafter a horizontal wellbore 14, formed by using some means of directional drilling, such as a diverter. The horizontal wellbore 14 is used to more completely and effectively reach formations bearing oil or other hydrocarbons. In FIG. 1, the vertical wellbore 12 has a casing 16 disposed therein while the horizontal wellbore 14 has no casing disposed therein.
After the wellbore 12 is formed and lined with casing 16, a string of production tubing 18 is run into the well 10 to provide a pathway for hydrocarbons to the surface of the well 10. The well 10 oftentimes has multiple hydrocarbon bearing formations, such as oil-bearing formations 20, 21, 22 and/or gas bearing formations 24. Typically, packers 26 are used to isolate one formation from another. The production tubing 18 generally includes multiple joints of screened tubing 28. To recover hydrocarbons from a formation where there is casing 16 disposed in the wellbore, such as at formations 20 and 21, perforations 30 are formed in the casing 16 and in the formation to allow the hydrocarbons to enter the wellscreen through the casing 16.
Each joint of screened tubing 28 typically includes a perforated inner tubing (not shown) surrounded by a wellscreen. The purpose of the wellscreen is to allow inflow of hydrocarbons into the production tubing 18 while blocking the flow of unwanted material. Each end of the wellscreen is generally welded to an end ring, which is coupled to the perforated inner tubing. The end rings are configured such that fluids or hydrocarbons generally cannot flow past the end rings. A sliding sleeve (not shown) may be positioned inside the perforated inner tubing. The sliding sleeve is generally used to open and close subsurface access openings (or perforations) disposed on the perforated inner tubing to inject fluid into the formation or to produce fluid from the formation. Without this sliding sleeve, each joint would not be able to inject fluid into the formation or to produce fluid from the formation. In this manner, each joint of screened tubing 28 typically includes a sliding sleeve. Thus, a production tubing for a formation that spans thousands of feet (e.g., a horizontal or lateral wellbore) generally consists of hundreds of joints of screened tubing, each having its own sliding sleeve. Since sliding sleeves are costly (e.g., about $15,000 to about $20,000 for each sleeve), the cost to complete a deep well having a depth of several thousand feet, for example, can be cost prohibitive, in view of the number of sliding sleeves used in the production tubing.
Therefore, a need exists for a more cost effective apparatus and method for controlling the flow of fluids into a production tubing.